Railway brake



T. S. TAYLOR RAILWAY BRAKE Aug. 16, 1966 4 Sheets-Sheet 1 Filed Dec. 12,1963 FIG. 6

INVENTOR. THOMAS S. TAYLOR ATTORNEYS Aug. 16, 1966 s TAYLOR 3,266,501

RAILWAY BRAKE Filed Dec. 12, 1963 4 Sheets-Sheet 2 FIG. 2

THOMAS s. TAYLOR ATTORNEYS INVENTOR.

Aug. 16, 1966 T. s. TAYLOR 3, 01

RAILWAY BRAKE Filed Dec. 12, 196-3 4 Sheets-Sheet 4 FIG. 4

INVENTOR. THOMAS S. TAYLOR ATTORNEYS United States Patent 3,266,601RAILWAY BRAKE Thomas S. Taylor, Suffern, N.Y., assignor to AmericanBrake Shoe Company, New York, N.Y., a corporation of Delaware Filed Dec.12, 1963, Ser. No. 330,192 20 (Ilaims. (Cl. 188-52) This inventionrelates to a brake unit for a railroad car, and more particularly, to abrake unit to be mounted on a truck of a railway car.

The present invention relates to a so-called package brake unit which ischaracterized by an individual air cylinder or cylinders carried by eachtruck of a railroad car. Preferably, the brake unit is mounted on aspring supported bolster so as not to be subject to direct rail shock,although some package brake units have been supported upon the truckside frames and thus have been unsprung masses subject to direct railshock.

Preferably, the package brake unit is mounted below the top surface ofthe bolster so as not to interfere with the various types of cardesigns, which are to be mounted on the bolster. While it has beenheretofore proposed to mount a plurality of cylinders on the truck,these cylinders were not controlled by suitable adjusters to adjust forslack in order to maintain the piston stroke and thereby the airpressure. Accordingly, the present device has for its principal object anovel package brake unit mounted completely beneath the top surface ofthe bolster and employing a cylinder with its air pressure and strokemaintained by a suitable adjuster and as a further object a singlecylinder with a comparatively long stroke operable through the bolsterunit to actuate each of brake beams on opposite sides of the truck.

The package brake of the present invention increases the braking forcewith increase in car loading by reason of its unique geometricconstruction wherein its force multiplying characteristics are changedwith increases and decreases in bolster movement due to weight. Morespecifically, and in accordance with a further object of the invention,a single force multiplying lever changes its point of intersection withrespect to a live lever of a conventional brake beam upon verticalmovement of the bolster so that the braking force becomes proportionalto the loading of the bolster. According to a further object of theinvention, an increase or decrease in weight on the bolster causes aproportional change in the braking force, and in the stroke of the fluidoperated piston of the cylinder, the stroke of the fluid operated pistonbeing controlled by an automatic slack adjuster.

While the construction of the package brake unit permits a limitedamount of proportional braking force change with a corresponding changein freight car loading, the package brake unit can advantageously beprovided with, according to a further object of the invention, anautomatic mechanism for changing the force multiplying characteristicsof the force multiplying lever so that the package brake unit can affordan empty brake force as well as a full brake force without theincorporation of a costly additional empty load brake unit, which hasheretofore been necessary to achieve complete compensation for an emptyload condition. Under a further object of the invention, an automaticslack adjuster compensates for changes in the stroke of the cylinder asthe automatic force multiplying mechanism is employed.

Another object of the invention is to enable the package brake unit toemploy the same standard, unmodified brake beams and brake struts of AARstandards in different weights of railroad cars, for example, seventy orninety ton railroad cars. Thus, under this object of the 3,266,661Patented August 16, 1966 invention, a brake unit canbe assembled withstandard elements and employed in trucks for varying weights of railroadcars by changing the fulcrum point of the force multiplying lever toincrease correspondingly the braking force for larger cars and todecrease correspondingly the braking force for lighter cars.

The present invention has as a further object the capability ofemploying either high friction shoes, typically of the composition type,or lower friction shoes typically exemplified by iron brake shoeswithout a decrease in efiiciency of the brake unit. A problem with acapability of employing both of these types of shoes has been that theiron brake shoe may be a much thicker brake shoe than composition brakeshoe so that an iron brake shoe undergoes a larger change in size withwear than a composition shoe which was thinner in the first instance.Thus, an object of the invention is a brake unit having the capabilityof adjusting its operating movements to provide a relatively constantbraking even though there has been a wearing away of iron brake shoes orof a composition type of brake shoe. Another object of the presentinvention is providing in a package brake unit the capability of beingable to employ either a low friction brake shoe or for a higher frictionbrake shoe.

Another object of the invention is the utilization of the package brakeunit in conjunction with a conventional hand brake mechanism whereby itshand brake pull rod can be directly employed to actuate the packagebrake to employ the needed braking force while causing the appropriatemovement of the piston of the cylinder. Under this object, the pistonrod of the air cylinder is protected from the weather elements by natureof its extending through the bolster and hence can remain extended forlong periods of time without deleterious effect on the piston rod.

An additional object of the invention is an automatic slack adjusterwhich is effected to cause movement of the piston both in pay out andtake up directions, and be operable with a brake operation.

According to the preferred embodiment of the invention, thecylinder-adjuster unit is mounted on one side of the bolster and has apiston whose piston rod goes through the bolster to actuate a forcemultiplying lever secured in a substantially horizontal manner on the0pposite side of the bolster. A live lever for actuating a brake beam isdisposed at an angle to instersect and to engage the horizontal leverwhile permitting relative vertical movement between the levers, due tochanges in load on the spring mounted bolster. As the bolster moves inresponse to weight changes, the effective length of the lever arm ischanged correspondingly to vary the multiplying eifect of the lever armand thus the braking force. The live lever is connected by a rod whichpasses under the bolster to a dead lever mounted on the opposite brakebeam. The dead lever is adapted to contact a movable lug on a slackadjuster which moves to compensate for changes in brake shoe thicknessdue to Wear or for changes in piston stroke resulting from changes inthe eifective lever ratio as cargo is added to or removed from the car.The slack adjuster, if automatic, is interconnected with the piston ofthe cylinder or with its directly driven members so as to change itsposition correspondingly with changes in force and the piston stroke asa result of force changing characteristics of the system.

Other and further objects of the present invention will be apparent fromthe following description and claims and are illustrated in theaccompanying drawings which, by way of illustration show a preferredembodiment of the present invention and the principles thereof and whatis now considered to be the best mode contemplated for applying theseprinciples. Other embodiments of the invention embodying the same orstructural changes may be made as desired by those skilled in the artwithout departing from the present invention and the purview of theappended claims.

In the drawings:

FIG. 1 is a perspective view of the truck of a railroad car equippedwith a brake unit of the present invention;

FIG. 2 is an enlarged plan view of a brake unit installed upon aconventional truck;

FIG. 3 is an end elevational view taken along the lines 33 of FIG. 2 inthe direction of the arrows;

FIG. 4 is an end elevational view showing the brake unit on a truckalong the line 44, FIG. 2 in the direction of the arrows;

FIG. 5 is an enlarged sectional view of the automatic slack adjuster andcylinder, according to the preferred embodiment of the invention; and

FIG. 6 is a diagrammatic view of an automatic mechanism for causing aproportional braking force for variances in car weight, according to thepreferred embodiment of the invention.

Referring now to the drawings, and more particularly to FIG. 1, there isshown a conventional railroad truck 10 for a railroad car, in which ismounted the brake unit of the present invention. The truck 10 includes aset of four wheels W mounted on a pair of spaced axles 11 and 12, theends of the axles being journaled in an opposed pair of side frames 13and 14. A centrally disposed bolster 15 spans the side frames 13 and 14.The bolster element 15 has its opposite ends mounted on springs 16carried by the side frames 13 and 14 and thereby the bolster 15 isisolated from the direct rail shock encountered by the wheels anddirectly transmitted to the side frames 13 and 14. Two of such trucks 10support a railroad car, and each of the trucks 10 is supplied with anindividual brake system confined to an associated truck to constitute aso-called package brake unit.

The brake unit of the present invention includes a brake cylinder 20,which, upon admission of fluid under pressure, causes an internal piston21, FIG. 5, to move a piston rod 22, FIG. 2, through an internal openingor bore 23 in the bolster 15 to move an outer end 25 of the piston rod22 to apply a braking force to a force multiplying lever 26 pivotallyconnected to the end 25 of the piston rod 22. The force multiplyinglever 26 is in contact with the upper portion of a live lever 28 andapplies the brake force thereto. This application of a braking force tothe upper end of live lever 28 by the force multiplying lever 26 causesthe live lever 28 to pivot about a central pivot pin 29 and thereby tothrust rearwardly a bottom-under rod 30. The bottom-under rod isarticulated by a pin 31 to the live lever 28 and is articulated by a pin33 to a dead lever 32. Thus, rightward movement of the bottomunder rod30, FIG. 2, pivots the dead lever 32 in a counterclockwise direction, asviewed in FIG. 2; and moves the brake beam 35 rightwardly, FIG. 2, toengage its brake shoes 38 with treads 39 on the rear wheels W.

The live lever 28 has its pivot pin 29 supported in a central strut 39of the front brake beam 40 to that the counterclockwise pivoting of thelive lever 28 to cause applying of the rear brakes is simultaneouslyaccompanied by movement of the front brake beam 40 leftwardly, as viewedin FIG. 2, to bring the front brake shoes 42 into engagement with thethreads 39 of the front wheels W. The brake beams 35 and 40 areconventional brake beams of AAR standards as are the live lever 28,bottom rod 30, and dead lever 32, which, together with the brake beams35 and 4t) constitute a standard bottomrod-under truck linkage system.

When the bottom rod 30 moves rightwardly, as viewed in FIG. 2, inresponse to a braking force, and once the shoes 38 are applied againstthe wheel treads 39, the upper free end 42 of the dead lever 32 isprevented from rotating further about a pivot pin 41 in a strut 43 ofthe brake beam 35 by a lug 44 on a slack adjuster 45. In this manner,the rightward thrust of bottom rod 30 causes the brake beam 35 totranslate rightwardly as viewed in FIG. 2 to apply the brake shoes 38against the wheel treads.

The slack adjuster 45 is secured to the side of the cylinder 2i) and/ orthe bolster 15. Both the cylinder 20 and slack adjuster 45 are disposedbeneath the upper surface of the bolster 15, as seen in FIGS. 1, 3 and4. Thus, the cylinder 20 will not preclude mounting of a car body on thebolster 15 which fits relatively close to the top of the bolster 15. Themounting of the cylinder 20 on the side of the bolster 15 opposite thelive lever 28 is advantageous in affording a long piston stroke. Becauseof the availability of a long piston stroke, the cylinder can be ofsmaller diameter than a comparable cylinder having a shorter stroke.

The brake beams 35 and 40 are supported in the usual manner by the sideframes 13 and 14 at spaced points outwardly near the wheels W to guidethe brake beams 35 and 40 to slide so as to carry the brake shoes intoengagement with the wheel. Inasmuch as the bolster 15 is springsupported, the bolster 15 is subject to moving vertically relative tothe side frames 13 and 14 and relative to the brake beams 35 and 40,particularly as the weight of the railroad car supported by the bolster15 is being varied due to increases or decreases in the loading of therailroad car. Since the cylinder 20 and adjuster 45 are directly mountedon the bolster 15, as are the connecting rod 25 and the forcemultiplying lever 26, these elements also partake of relative movementwith respect to the live lever 28 and the brake beam 40. As the bolster15 moves relative to the side frames 15, the horizontal lever 26 andadjuster lug 44 move relative to the upper ends of the dead and livelevers 28 and 32 respectively.

Normally, a brake unit delivers a predetermined amount of brake shoeload irrespective of the loading in the railroad car. However, the AARstandards for brake shoe loads call for a maximum brake shoe load not toexceed a certain percentage of the car weight empty and a minimum brakeshoe load not less than another percentage of the total car weightloaded. With the ad vent of special types of cars and the employment oflightweight, high strength steels and aluminum in car bodies, the brakeshoe load needed for a fully loaded car, will in many cases, exceed themaximum permissible brake shoe load for an empty car. Thus, resort ismade to the provision, in many instances, of an additional empty loadbrake mechanism. Manifestly, the requirement for a special empty loadbrake mechanism is an expensive addition to the braking system for therailroad car.

The present invention compensates for changes in loading of the railroadcar'by changing the multiplying effect of the force multiplying lever26, so that the amount of braking force applied by the force multiplyinglever 26, to the live lever 28 increases as the weight of the railroadcar increases and decreases as the weight of the railroad car decreases.More specifically, the force multiplying lever 26 is disposed in agenerally horizontal plane, as best seen in FIG. 4 with one endpivotally connected by a pin 50 to the piston rod 22, and with theopposite end pivoted by a pin 51 to a fulcrum post 52 secured in asuitable manner to the bolster 15. As best seen in FIG. 4, the livelever 28 extends upwardly and leftwardly in front of the horizontallever 26, and intersects the horizontal lever 26 at a contact orreaction point 55. The live lever 28 of a conventional brake beam isdisposed at nominally 40 to the vertical, FIG. 4, so that as the lever26 moves up and down relative to the end of the live lever 28, thecontact or intersection point 55 between these levers moveshorizontally. Thus, as the bolster 15, air cylinder 20 and forcemultiplying lever 26 move upwardly and downwardly relative to therelatively stationary live lever 28, brake beam 40, and the side frames13 and 14, in response to changes in weight of the railroad carsupported on the truck 10, the intersection point 55 between thehorizontal lever 26 and live lever 28 also moves transversely to varythe effective length of the force multiplying lever arm between thepoint 55 and the fulcrum point 51 of the lever 26.

From a force standpoint, the total moment of force of the cylinder forceabout pivot point 51 remains constant since the force applied to the endof the force multiplying lever 26 by the piston rod 22 is unchanged.That is, the piston force is operative over the length of the lever armfrom pin 50 to the fulcrum pin 51. Hence, the moment of force remainsthe same. However, because of the shorter distance or effective leverarm between the reaction point 55 and pin 51, the force at the reactionpoint 55 increases in order to maintain the two opposing moments offorce in balance. However, this increase in force applied to the livelever 28 at the reaction point 55 is offset to some extent because theeffective length of live lever arm 28 is shortened as the reaction point55 moves toward the pivot pin 29, thereby decreasing the moment of forceor braking load, from that which would be available, if the effectivelever arm of the live lever 28 were not shortened as a result of thebolster 15 moving downwardly.

Thus, the brake load varies automatically with changes in freight carloading due to the geometrical relationship between the forcemultiplying lever 26 and live lever 28. The change in braking force orload experienced is approximately in the range of which will not be asufficient change in brake load to assure that all cars employing thepresent invention need not have an auxiliary empty load brake unit.Nonetheless, the present invention will, in many cases, eliminate thenecessity for empty load brake equipment in addition to the regularbrake package.

Because of the unique construction of the present package brake, it canbe readily adapted for employment in various sizes and weights ofrailroad cars. For example, in the embodiment of the inventionillustrated herein, the brake unit is shown employed in a 90 tonrailroad car, whereas to adapt the same package brake unit for a 70 tonrailroad car, requires only the lengthening of the force multiplyinglever arm about two inches. To accomplish this, for example, the leverarm 26 could be provided with a series of spaced holes therein in whichthe pivot pin 51 could be placed so as to employ the same lever 26 whenchanging the effective distance between the fulcrum pin 51 and thepivotal connection 50 with the connecting rod 25. The compression orfulcrum rod 56 secured to the bolster may likewise be moved between aseries of positions when changing the efiective length of the forcemultiplying lever 26. Thus, it will be appreciated that an importantaspect of the present invention is its ready applicability to varyingsizes and weights of railroad cars merely by providing separate andvarying lengths of force multiplying levers 26, or by changing thefulcrum point for a single force multiplying lever by moving a pivot pinbetween a series of pivot pin holes therefor.

Since the brake beams 35 and 40, as well as the live lever 28, bottomrod 30, and dead lever 32 are standard AAR bottom-under brake beamequipment, the package brake of the present invention advantageously canbe repaired with normally inventoried brake beams and componentsthereof. Also, a railroad car having a rodunder brake system can bereadily fitted with the present cylinder 20, adjuster 45 and lever 26.

As hereinbefore explained, the brake force applied to the live lever 28can be varied either by changing the length of the force multiplying arm26, and/or an automatic adjustment in the distance between the reactionpoint 55 and the fulcrum 51 as the lever 26 moves vertically relative tolive lever 28. Advantage is taken of both of these concepts to provide asimple mechanical arrangement whereby the amount of braking force can bevaried automatically; and, more significantly, to approximate moreclosely an empty load brake force for most railroad cars, while stillproviding the maximum brake shoe load for these cars in the loadedcondition.

Referring now to FIG. 6, the bolster 15 is shown in the full lineposition corresponding to an empty car condition, at which position, thereaction point 55 marks the intersection between the horizontal, forcemultiplying arm 26 and the intersecting live lever arm 28. The pistonrod 22 is connected to the live lever 26 by the pin 50 at its left endand is fulcrumed at its right end by a pin 51 on a sliding block 60. Thesliding block 60 is employed in lieu of the fixed compression rod 56 andserves as a fulcrum for the force multiplying lever 26. The slidingblock 60 is adapted to slide horizontally along the bolster 15 to theposition 60' under influence of a compression spring 61 as the bolstermoves downwardly the full extent under a heavy load condition. That is,the slide 60 is biased by a compression spring 61 to move leftwardly tothe position 60' as the bolster 15 moves downwardly to the phantom lineposition under the weight of a full load.

The end of the sliding block 60 has secured thereto a chain 62 or thelike which extends from the block 60, around a pulley 63 and to thebrake beam 40.

Since the brake beam 40 remains stationary, upward movement of thebolster 15, for example, in response to decrease in load of the railroadcar exerts a force on the cable 12 to cause the pulley 63 to rotate in aclockwise direction, as viewed in FIG. 6, as the cable 62 pulls thesliding block 60 rightwardly against the resistance of the spring 61thereby lengthening the effective lever arm between the reactance point55 and the block 60. Thus, with the longer effective lever arm, thebrake force applied to live lever 28 is decreased considerably from thebrake force applied for a full load, wherein the effective length of thelever arm is between the point 55' and the sliding block position 60. Itwill be understood that the sliding block 60 is limited to horizontalsliding movement only along the bolster 15; but because the bolster 15partakes of a simultaneous vertical movement as block slideshorizontally, the block 60 achieve the vertically displaced position 60'at full load condition of the railroad car.

The amount of sliding movement of the block 68 is equal to the amount ofvertical movement of the bolster 15, as shown in FIG. 6. However, byemploying a suitable lever or an equivalent, the amount of horizontalsliding movement of the block 60 can be multiplied so as to be greaterthan the amount of vertical movement of the bolster. Thus, an evengreater change in force can be readily accomplished between an empty andfull load condition of the railroad car.

It is to be noted that when the force multiplying lever 26 movesvertically with respect to the live lever 28, the amount of movement ofrotation of the live lever 28 will be changed for a fixed piston strokeand accordingly the amount of movement of the bottom rod 30 also will bechanged. The slack adjuster 45 advantageously compensates for changes inamounts of rotation of the live lever and assures that live lever 28 andbottom rod 30 move to apply the brake shoes 38 and 42. Also, the slackadjuster 45 performs the function of compensating for brake shoe wear.

The slack adjuster 45 can be manually adjusted to compensate for changessuch as brake shoe wear or shoe replacement by turning an exteriorhandle 80, FIG. 5, extending outwardly of an adjuster housing wall 81 ofthe adjuster 45. The handle is fixedly secured to a threaded shaft 82,which has one end rotatably supported in a bearing 83 carried in thehousing wall 81.

The threaded shaft 82 is permitted to rotate within the bearing 83, butis prevented from moving axially by a thrust collar 84 secured to theshaft 82 interior of the housing wall 81 and by a thrust collar 85 onthe handle 80 7 exterior of the housing Wall 81. Turning of the handle80 rotates the threaded shaft 82, and turns its threads 88 in aninteriorally threaded collar 89 from which extends adjuster lug 44through a slotted opening 90 in an adjuster housing wall 91. The lug 44thus is held against rotation with the threaded shaft 82 while permittedto move axially as the threaded shaft 82 turns. Secured to the interiorend of the threaded shaft 82 is a drive gear 94 which is adapted to matewith an idler gear 95 in a manner hereinafter explained.

As will be understood from a comparison of FIGS. 2 and 5, rightwardmovement of the adjuster lug 44 causes the dead lever 32 and the brakebeam 35 to move the brake beam 35 and brake shoe 38 closer to the wheelsW and take up looseness or slack. Thus, even with worn shoes or asmaller amount of rotation of the live lever 28, the adjuster lug 44 hastaken up the slack and assured movement of the brake beam 40 leftwardlyto bring the brake shoes 42 against the wheels W. In this manner, byturning the handle 80 and the threaded portion 88 of the shaft 82 theadjuster lug 44 may be moved rightwardly, as viewed in FIGS. 2 and totake up slack. Manifestly, if new shoes are being employed, the handle80 can be rotated in the opposite direction to rotate the adjacent lug44 leftwardly to accommodate such increased thickness in shoe size, thisdirection being called the pay out direction, therefore the live lever28 and bottom rod 30 can still partake of their normal movements.

In the interior of the adjuster 45 is a longitudinally extending wall 98terminating a housing wall 99 to constitute with an exterior housingwall 100, the fluid receiving cylinder in which reciprocates the piston21.

The wall 99 has an aperture therein in which is disposed a slideableshaft 105. On the leftward end of shaft 105 is journaled an idler gear95 for free rotation about its supporting shaft 105. As the piston 21move s leftwardly under fluid pressure through a distance correspondingto its nominal stroke, the piston 21 moves a disk 101 into engagementwith the top of a compression spring 102, which is operative to engage acollar 104 on shaft 105 and to move the gear 95 leftwardly against theresistance of a second compression spring 108. The spring rates ofsprings 102 and 108 are balanced so that when the piston 21 movesthrough its nominal stroke, the idler gear 95 is in meshing egagementwith gears 94 and 112. Leftward movement of shaft 105 and gear 95 islimited by a projecting stop 109 secured to the housing wall 97. Thespring 102 is secured to the housing wall 99 in a suitable manner and ispreferably guided by a cylindrical tube (not shown) coaxial with thespring 102.

The gear 112 is formed on the outer peripheral surface of a ball-nut113, which is disposed for rotation on a threaded sleeve 115. Thethreaded sleeve 115 has a central bore, through which extends the pistonrod 22. The sleeve 115 is limited against axial movement leftwardly by atoothed collar 116 formed on the outer end of the piston rod 22. Thetoothed collar 116 is adapted for tooth engagement with a complementarytoothed collar or end portion 117 on the threaded sleeve 115. The toothportion 117 of the sleeve 115 is biased into engagement with the teeth116 of the piston rod 22 by a compression spring 120 disposed betweenthe interior surface 121 of the piston 21 and a slideable collar 122,which is in engagement with a bearing 123 disposed againstthe end wall125 of the threaded sleeve 2115. Thus, the compression spring 120 forcesthe slidable collar 122, bearing 123 and sleeve 115 to urge the teeth117 of sleeve 115 into the teeth 116 of the piston rod 22. The bearing123 serves to permit the sleeve 115 to rotate more freely against theend of spring 120 than would be the case if the spring 120 were directlyabutted against the end surface 125 of the sleeve 115.

When the piston 21 begins to move under fluid pressure, the piston rod22 carrying sleeve 115 moves the disk 101 on the sleeve 115 against thespring 102. As the piston 21 and piston rod 22 move further leftwardly,the spring 102 begins to move the shaft 105 leftwardly against theresistance of spring 108. When the piston 21 moves through its nominalstroke, idler gear on shaft is moved to mesh with the gears 94 and 112.At this position, the reaction load on lug 44 is balanced by the fluidpressure force on the piston 21. Thus, the gear 94 is locked againstrotation by the gears-95 and 112 since the gear 112 cannot rotate thethreaded shaft 115, which shaft is locked by its toothed collar 117engaging the teeth 116 of the non-rotatable piston rod 22.

If the brake shoe load appears before the normal stroke of the piston 21is obtained, the reaction load acts on the adjuster lug 44 to cause thethreaded screw 88 to turn, thereby permitting the adjuster lug 44 tomove in the pay out direction, leftwardly. Thus, further movement ofpiston rod 22 does not increase the brake shoe load as further movementof the piston 22 is compensated by leftward movement of the adjusterl-ug 44. When the piston rod 22 moves a sufficient distance to moveidler gear 95 into meshing engagement with the gear 94, the threadedshaft 82 is locked against being turned by the leftward movement of thelug 44. Hence, the adjuster lug 44 is locked from further movement, theproper brake shoe load is being applied with the piston 21 movingthrough its nominal stroke.

Upon releasing the brakes, the fluid pressure leaves the cylinder cavity130, and an internal return spring 131 acting on the inner face 121 ofthe piston 21 moves the piston 21 rightwardly, and the disk 101 movingtherewith permits the compression spring 108 to disengage the idler gear95 from the drive gear 94 on the adjuster shaft 82. Thus, the adjusterlug 44 will retain this new pay out position.

If the brake shoe load is not obtained by the time the piston 21 hasmoved through its nominal stroke and has caused the idler gear 95 to bein meshing engagement with the driver gear 94 and the gear 112, furthermovement of the piston 21 leftwardly compresses the spring 120. Sincethe gear 112 is locked against rotation by meshed idler gear 95, gear112 holds sleeve stationary as the piston shaft 22 moves leftwardly andseparates the toothed collars 116 and 117. When the tooth elements 116and 117 are disengaged, further leftward movement of the piston 22 andthe brake shoe load acting through the lug 44 and the threaded shaft 88rotate idler gear 95 and the gear 112 on the ball-nut 113. The ball-nut1 13 is limited by bearings 135 on casting walls 136 and 137 from axialmovement. Thus, rotation of the gear 112 causes the threaded sleeve 115to move leftwardly toward the collar 116 on the shaft 22 and to engagethe clutch collars 116 and 117 to stop the piston stroke.

When the air pressure on the piston 21 is released, the compressionspring 131 moves the piston 21 rightwardly, and the threaded sleeve 115moving through the ball-nut 113 rotates the gears 95 and 94 to move theadjusting lug 44 leftwardly, there being no braking force, that is, noreaction force opposing this leftward movement of the adjusting lug 44.Thus on the return or retract-ion stroke of the piston 20, the adjustinglug 44 moves to take up any existing slack. When the piston rod 22 movesrightwardly a suflicient distance, the disk 101 on the sleeve 115 willrelease compression spring 102 and the spring 108 is operative todisengage the idler gear 95 so that the remainder of movement of thepiston in-rightward direction is accompanied merely by rotation of theball-nut 113 without accompanying rotation of the drive gear 94 andadjuster lug 44.

The package brake unit of the present invention is readily adapted foroperation by a hand 'brake since it is only necessary to attach a handbrake pull rod 150, FIG. 2, to the pin 50, so that the pull rod actuatesthe force multiplying lever 26. Upon application of the hand brake, thepiston rod 22 can be retained outwardly of the cylinder 20 forconsiderable periods of time without adverse effects on the piston rod22, since the piston rod is disposed in a cavity within a bolster 15,and thereby protected from the weather. Generally speaking, it is notdesirable to move the piston rod with the hand brake, since the pistonrod would be exposed to the weather elements, and, for instance, couldbecome iced and frozen in position to maintain the brake applyingposition upon release of the hand brake. A bushing or seal can beprovided to guide the piston rod 22 as well as to seal the bore 23 inthe bolster against the elements. With the present invention, release ofthe hand brake permits the return spring 131 to return the piston 21 toits proper position. Also, the automatic slack adjuster 45 willautomatically limit the hand brake stroke to a predetermined properamount. Inasmuch as the conventional hand brake generates twice theoutput forces of the cylinder 20, a hand brake pull rod 150 need beconnected to only one truck of a railroad car, thus saving the necessityof providing a second hand brake mechanism for the second truck of therailroad car.

From the foregoing, it will be seen that the package brake unit is soconstructed as to be disposed completely below the level of the bolster,and is so designed to provide changing braking forces between empty loadand full load conditions of the car, thereby eliminating the need, inmany instances, for a costly empty load brake equipment. Whereadditional adjustment or compensation is required for empty loadcondition, the present invention is provided with a movable fulcrumwhich varies the length of the force multiplying lever so as to aiford agreater compensation than that available due to the geometry of thelinkage employed.

Also, it will be seen that an automatic slack adjuster can be providedto compensate for changes in piston stroke due to the change in leverratios and to assure the proper brake shoe load, as applied to the carwheels, irrespective whether or not, relatively thick or relatively thinbrake shoes are applied.

Moreover, the package brake is readily actuatable by a hand brakemechanism, which need merely be attached to the end of the forcemultiplying lever to cause the proper piston stroke, and the piston rodis permitted to move with the application of the hand brake, inasmuch asit is protected by the bolster.

Hence, while preferred embodiments of the invention have been describedand illustrated, it is to be understood that they are capable ofvariation and modification, and I therefore do not wish to be limited tothe precise details set forth, but desire to avail myself of suchchanges and alterations as fall within the purview of the followingclaims.

I claim:

1. In a brake unit adapted to be secured to the truck of a railroad car,wherein a bolster of the truck is spring mounted for vertical movementrelative to side frames of the truck; a pair of brake beams disposed onopposite sides of the bolster, each of said brake means being movable onsaid side frames; brake beam operating means including a beam operatinglever extending upwardly from one of said brake beams at an angle to thevertical; cylinder means secured to said bolster for vertical movementtherewith, said cylinder means having a piston means movable in responseto fluid pressure within said cylinder to generate a braking force; aforce multiplying lever means operated by said piston means of saidcylinder means, said force multiplying lever means being mounted on saidbolster, and partaking of vertical movement with the bolster withrespect to said beam operating lever, said force multiplying lever meansengageable with said beam operating lever at a point of engagement, saidforce mul tiplying lever means movable vertically relative to said beamoperating lever to change the point of engagement with said beamoperating lever and said force multiplying lever means as said forcemultiplying lever means moves with said bolster.

2. In a brake unit adapted to be secured to the truck of a railroad carwherein a bolster in the truck is spring mounted for vertical movementrelative to side frames of a truck, live lever and dead lever brakebeams disposed on opposite sides of the truck and movable with respectto said side frames; a cylinder means secured to one side of the bolsterhaving said dead lever brake beam and having a piston means with anoperative stroke through said bolster to supply the brake operatingforce for said live lever brake beam, slack adjuster means secured tosaid bolster on said one side of said bolster and engageable by saiddead lever brake beam, and a lever means engageable with said pistonmeans to operate said brake beams, said lever means being disposed onthe other side of the bolster opposite said cylinder means and saidslack adjuster.

3. The brake unit of claim 1 wherein said cylinder means is disposedbeneath the upper top surface of said bolster so that said cylindermeans does not engage the body of a railroad car mounted on saidbolster.

4. The brake unit of claim 2 wherein said bolster has an interior coredarea, a hand brake operating means attached to said lever means foroperating said lever means to apply a brake force to said braking beams,said piston means being movable by said lever means and being protectedfrom the weather elements by being disposed at least partially in saidcored area in said bolster.

5. In a brake unit adapted to be secured to the truck of a railroad carwherein the bolster in the truck is spring mounted for vertical movementrelative to side frames of the truck: a pair of brake beams disposed onopposite sides of the truck and supported for movement by said sideframes, one of said brake beams having a beam operating lever extendingvertically at an inclination to the normal; a power operated cylindermeans mounted on said bolster and adapted to generate the braking forcefor said brake beams; a horizontal lever means having one end secured tosaid cylinder means for rotational movement by said cylinder means abouta pivotable connection of the opposite end of the lever means with thebolster; said lever means engageable with said beam operating lever at apoint of contact and actuating said beam operating lever in response tobeing pivoted by said cylinder means, vertical movement of said bolsterand said horizontal lever means thereon changing the point of contactbetween said horizontal lever means and said beam operting lever andchanging the braking force applied to the beam operating lever withloading of the railroad car.

6. The brake unit of claim 5 including another horizontal lever means,to adapt the brake unit for a railroad car of lower rated capacity forweight, said another horizontal lever means of longer effective lengthso as to increase the distance between the fulcrum point and theconnection of said horizontal lever means with the cylinder means.

7. In a brake unit adapted to be secured to the truck of a railroad car,wherein a bolster of the truck is spring mounted for vertical movementrelative to side frames of the truck: a pair of brake beams disposed onopposite sides of the bolster, each of said brake beams being movable onsaid side frames; beam operating means including a beam operating leverextending upwardly from one of said brake beams at an angle to thevertical; cylinder means secured to said bolster for vertical movementtherewith, said cylinder means having a piston means movable in responseto fluid pressure within said cylinder to generate a braking force; aforce multiplying lever means operated by the piston means of saidcylinder means, said force multiplying lever means being pivotallymounted on said bolster and partaking of vertical movement with thebolster with respect to said beam operating lever, said forcemultiplying lever means movable verti cally relative to said beamoperating lever, said force multiplying lever means engaging said beamoperating lever at a contact point and said contact point changingbetween said beam operating lever and said force multiplying lever meansas said force multiplying lever means moves with said bolster; and meansmovable in response to vertical movement of the bolster to change thepoint of pivotally mounting of said force multiplying lever means onsaid bolster so that said braking force varies with changes withvertical movement of the bolster.

8. In a brake unit adapted to be secured to the truck of a railroad carwherein a bolster in the truck is spring mounted for vertical movementrelative to side frames of a truck: brake beams disposed on oppositesides of the truck and movable with respect to said side frames; acylinder means secured to one side of the bolster and having a pistonwith an operative stroke through a bore in said bolster and adapted tosupply the brake Operating force for said brake beams, lever meansoperable by said piston to operate said brake means, said lever meansbeing disposed on the side of the bolster opposite said cylinder means;a movable block mounted on said bolster; said lever means having apivotal connection with said movable block; biasing means biasing saidblock in one direction; and connecting means extending between saidmovable block and said brake beam means to move said block in responseto vertical movement of said bolster in an opposite direction to saidone direction against the force of said baising means.

9. In a brake unit adapted to be secured to the truck of a railroad carwherein a bolster of the truck is spring mounted for vertical movementrelative to side frames of the truck: a pair of brake beams disposed onopposite sides of the bolster, each of said brake beams being movable onsaid side frames; a live, beam operating lever extending vertically fromone of said brake beams at an inclination to the normal; a dead lever onsaid other of said brake beams; cylinder means secured to said bolsterfor vertical movement therewith, said cylinder means having a pistonmovable in response to fluid pressure within said cylinder means togenerate a braking force; a force multiplying lever means operated bythe piston of said cylinder means, said force multiplying lever meansbeing mounted on said bolster, and partaking of vertical movement withthe bolster with respect to said beam operating lever, said forcemultiplying lever means adapted to move vertically relative to said beamoperating lever and to change an intersecting contact point between saidbeam operating lever and said force multiplying lever means as saidforce multiplying lever means with said bolster; and an automatic slackadjuster means mounted on said bolster and having a portion forengagement with said dead lever.

10, In a brake unit for a railroad car having a truck with a bolster andhaving one brake beam operated by a live lever and another brake beamoperated by a dead lever and with a bottom rod joining the live leverand dead lever, a power cylinder means disposed on one side of thebolster with said dead lever; a piston rod means operable through a borein the bolster; a horizontal force multiplying lever having one end inpivotal connection with said piston rod means and having its oppositeend fulcrumed on said bolster, said horizontal lever being positionedadjacent said live lever to engage said live lever at a contact pointand to rotate said live lever in response to operation of said powercylinder means, said horizontal force multiplying lever movingvertically with said bolster and changing the ratio of distances betweenthe pivotal connection and the contact point, and the contact point andthe fulcrum point.

11. In a brake unit for a railroad car having a truck with a bolster andhaving one brake beam operated by a live lever and another brake beamoperated by a dead lever and with a bottom rod joining the live leverand dead lever; a power cylinder means disposed on the side of thebolster with said dead lever; a piston rod means operable through a borein the bolster; a force multiplying lever disposed horizontally andhaving one end in pivotal connection with said piston rod means andhaving its opposite end fulcrumed on said bolster, said horizon tallever being positioned adjacent said live lever and engageable with saidlive lever at a contact point and rotating said live lever in responseto operation of said power cylinder means, said horizontal forcemultiplying lever moving vertically with said bolster and changing theratio'of distances between the pivotal connection and the contact pointand the contact point and the fulcrum point; and an automatic slackadjuster means mounted on said bolster for regulating the piston strokeof said piston rod means with changes in position of said contact pointbetween said horizontal force multiplying lever and said brake beamlever that cause change in the amount of rotation of said live lever bysaid force multiplying lever.

12. In a brake unit for a railroad car having a truck with a bolster andhaving one brake beam operated by a live lever and another brake beamoperated by a dead lever and with a bottom rod joining the live leverand dead lever: a power cylinder means disposed on one side of thebolster with said dead lever; a piston rod means operable through a borein the bolster; a horizontal force multiplying lever having one end inpivotal connection with said piston rod means and having its oppositeend fulcrumed on said bolster, said horizontal lever being positionedadjacent said live lever and adapted to engage said live lever at acontact point and adapted to rotate said live lever in response tooperation of said power cylinder means, said horizontal forcemultiplying lever moving vertically with said bolster and changing theratio of distances between the pivotal connection and the contact point,and the contact point and the fulcrum point; and an automatic slackadjuster means mounted on said .bolster, said slack adjuster having amovable lug in sliding contact with a free end of said dead lever.

13. In a brake unit for a railroad car having a truck with a bolster andhaving one brake beam operated by a live lever and another brake beamoperated by a dead lever and with a bottom rod joining the live leverand dead lever, a power cylinder means disposed on one side of thebolster with said dead lever and disposed beneath the upper surface ofsaid bolster to be clear of interference with the railroad car; a pistonrod means operable through a bore in the bolster; a horizontal forcemultiplying lever having one end in pivotal connection with said pistonrod means and having its opposite end fulcrumed on said bolster, saidhorizontal lever being positioned adjacent said live lever engageablewith said live lever at a constant point and rotating said live lever inresponse to operation of said power cylinder means, said horizontalforce multipying lever moving vertically with said bolster and changingthe ratio of distances between the pivotal connection and the contactpoint, and the contact point and the fulcrum point; and an automaticslack adjuster means mounted on said bolster beneath the upper surfaceof said bolster and associated with said piston rod means to compensatefor a change in the amount of rotation of said live lever by said forcemultiplying lever.

14. In a brake unit for a railroad car having a truck with a movablebolster and having one brake beam operated by a live lever and anotherbrake beam operated by a dead lever and with a bottom rod joining thelive lever and dead lever, a power cylinder means disposed on one sideof the bolster with said dead lever; a piston rod means operable througha bore in the bolster; a horizontal force multiplying lever having oneend in pivotal connection with said piston rod means, mounting means ata fulcrum point mounting the opposite end of said horizontal lever onsaid bolster; said horizontal lever being positioned adjacent said livelever to engage said live lever at a contact point and adapted to rotatesaid live lever in response to operation of said power cylinder means,said horizontal force multiplying lever moving vertically with saidbolster and changing the ratio of distances between the pivot-a1connection and the contact 13 point, and the contact point and thefulcrum point; and operating means on said movable bolster and connectedto the truck and said mounting means, vertical movement of the bolsterto relative to said brake beams actuating said operating means to movesaid mounting means and thereby the point of pivotally mounting of saidforce multiplying lever on said bolster so that the braking forceapplied to said live lever changes with vertical movement of thebolster.

15. In a brake unit for a railroad car having a truck with a bolster andhaving one brake beam operated by a live lever and another brake beamoperated by a dead lever and with a bottom rod joining the live leverand dead lever: a power cylinder means disposed on the side of thebolster with said dead lever; a piston rod means operable through a borein the bolster; a horizontal force multiplying lever having one end inpivotal connection with said piston rod means, mounting means mountingthe opposite end of said horizontal lever on said bolster; saidhorizontal lever having its opposite end fulcrumed on said mountingmeans, said horizontal lever being positioned adjacent said live leverand engageable said live lever at a contact point and rotating said livelever in response to operation of said power cylinder means, saidhorizontal force multiplying lever moving vertically with said bolsterand changing the ratio of distances between the pivotal connection andthe contact point and between the contact point and the fulcrum point;an automtaic slack adjuster means mounted on said bolster forcontrolling the piston stroke of said piston rod means with changes inposition of said contact point between said horizontal force multiplyinglever and said live lever and compensating for a change in the amount ofrotation of said live lever by said force multiplying lever; operatingmeans operable for changing the point of pivoting of said horizontallever on said bolster with changes in vertical movement of said bolster,said mounting means including a block mounted on said bolster forhorizontal sliding movement, said operating means including spring meansbiasing said sliding block to a first predetermined position, and meansinterconnecting said sliding block and one of said brake beams to movesaid sliding block against the bias of said spring means in response tovertical movement of said bolster relative to said one of the brakebeams.

16. In a brake unit for a railroad car having a truck with a bolster andhaving one brake beam operated by a live lever and another brake beamoperated by a dead lever and with a bottom rod joining the live leverand dead lever: a power cylinder means disposed on the side of thebolster with said dead lever; a piston rod means operable through a borein the bolster; a horizontal force multiplying lever having one end inpivotal connection with said piston rod means and having its oppositeend fulcrumed on said bolster, said horizontal lever being positionedadjacent said live lever and adapted to contact said live lever at acontact point and to rotate said live lever in response to operation ofsaid power cylinder means, said horizontal force multiplying levermoving vertically with said bolster and changing the ratio of distancesbetween the pivotal connection and the contact point, and the contactpoint and the fulcrum point; and an automatic slack adjuster meansmounted on said bolster for controlling the stroke of said piston rodmeans as changes in position of said contact point between saidhorizontal force multiplying lever and said live lever cause a change inthe amount of rotation of said live lever by said force multiplyinglever; said slack adjuster means including a lug movable against anupper and free end of said dead lever, a threaded shaft carrying saidlug for movement in response to rotation of said shaft, to move said lugand said dead lever and thereby said brake beams to take up slack or topay out slack, a drive gear secured on said threaded shaft and operableto turn with said threaded shaft, an idler gear'movable into engagementwith said drive gear in response to movement of said piston rod meansthrough a predetermined stroke, said piston rod means including a pistonand a piston rod, means biasing said idler gear from meshing engagementwith said driving gear when said piston has returned a predetermineddistance on its return stroke, a third gear adapted to be in meshingengagement with said idler gear when said idler gear is in position tomesh with said drive gear, a screw thread operable for turning saidthird gear with movement of said piston, said screw thread operable tolock said third gear against rotation when said piston has moved throughits nominal stroke and thereby lock said drive gear, threaded shaft andlug against pay out or adjust slack movement.

17. The brake unit of claim 16 wherein said piston rod has a toothsurface thereon, and wherein an axially movable sleeve is carried onsaid piston rod and has said threaded screw thereon, said threadedsleeve having a tooth end for engagement with said tooth surface on saidpiston rod to lock said sleeve and said screw thread against rotation bysaid third gear, spring means biasing said threaded sleeve to engage itstooth surface with said tooth surface on said piston rod, movement ofsaid piston rod when said gears are meshed causing said spring to becompressed and said piston rod to move to separate its tooth surfacefrom the tooth surface on said threaded sleeve.

18. A brake slack adjuster adapted to be employed with a movable pistonof a brake cylinder, comprising a housing; a threaded shaft journaled insaid housing for rotational movement; an adjuster lug axially movablealong said threaded shaft in response to rotation of said threadedshaft; a drive gear secured to said threaded shaft and rotatable withsaid threaded shaft; an idler gear biased to a position out of meshingengagement with said gear and movable by said piston into meshingengagement with said gear and movable by said piston into meshingengagement with said driving gear; a third gear adapted to be driven bysaid idler gear when said idler gear is in meshing engagement with saiddrive gear; and a screw thread for driving said third gear, idler gear,and drive gear so as to move said lug to take up slack when the brakesare released, said third gear being locked against rotation during theapplication stroke of said piston.

19. A brake slack adjuster adapted to be employed with a movable pistonand piston rod of a brake cylinder com prising a housing; a threadedshaft journaled in said housing for rotational movement; an adjuster lugaxially movable along said threaded shaft in response to rotation ofsaid threaded shaft; a drive gear secured to said threaded shaft androtatable with said threaded shaft; an idler gear biased to a positionout of meshing engagement with said drive gear and movable by saidpiston into meshing engagement with said drive gear; a third gearaligned for meshing engagement with said idler gear; a threaded sleeveaxially slideable on the piston rod of said piston, said threaded sleeveadapted to turn said third gear in response to movement of a piston in acylinder with which said slack adjuster is associated, said piston rodhaving a first end with a tooth surface; a complementary toothed surfaceon the end of said sleeve for tooth engagement with said tooth surfaceon said piston rod, spring means biasing said threaded sleeve to engageits tooth surface with said tooth surface on said piston rod; movementof said piston rod when said idler gear is in meshing engagement withsaid drive gear and said third gear, causing said spring to compress andsaid tooth surfaces to separate, whereby retraction of said piston rodcauses said threaded sleeve to rotate said gears and to move said lug inan adjusting direction.

20. In a brake unit adapted to be secured to the truck of a railroadcar, wherein a bolster of the truck is spring mounted for verticalmovement relative to side frames of the truck: a pair of brake beamsdisposed on opposite sides of the bolster, each of said brake beamsbeing movable on said side frames; brake beam operating means includinga live lever, a dead lever, and a connecting rod between said live leverand said dead lever, said live lever extending upwardly from one of saidbrake beams at an angle to the vertical; cylinder means secured to saidbolster for vertical movement therewith, said cylinder means having apiston means movable in response to fluid pressure within said cylinderto generate .a braking force; and a camming means on said bolster andconnected to said piston means and engageable with said live lever torotate said live lever of said brake beam operating lever, said cammingmeans adapted to contact said live lever at difierent points thereon assaid camming means moves vertically with said bolster and with thepiston means 18 relative to said live lever so that the braking forceapplied to the live lever changes with loading of the railroad car.

References Cited by the Examiner UNITED STATES PATENTS 283,368 8/1883Barratt. 2,181,041 11/1939 Baselt 188-52 2,885,034 5/1959 Holin 188-1952,973,840 3/1961 Newell 188-196 3,043,406 7/1962 Lans-son 188-1963,101,814 8/1963 Newell 188-153 X 3,120,881 2/1964 Davis 188-195 DUANEA. REGER, Primary Examiner.

2. IN A BRAKE UNIT ADAPTED TO BE SECURED TO THE TRUCK OF A RAILROAD CARWHEREIN A BOLSTER IN THE TRUCK IS SPRING MOUNTED FOR VERTICAL MOVEMENTRELATIVE TO SIDE FRAMES OF A TRUCK, LIVE LEVER AND DEAD LEVER BRAKEBEAMS DISPOSED ON OPPOSITE SIDES OF THE TRUCK AND MOVABLE WITH RESPECTTO SAID SIDE FRAMES; A CYLINDER MEANS SECURED TO ONE SIDE OF THE BOLSTERHAVING SAID DEAD LEVER BRAKE BEAM AND HAVING A PISTON MEANS WITH ANOPERATIVE STROKE THROUGH SAID BOLSTER TO SUPPLY THE BRAKE OPERATINGFORCE OF SAID LIVE LEVER BRAKE BEAM, SLACK ADJUSTER MEANS SECURED TOSAID BOLSTER ON SAID ONE SIDE OF SAID BOLSTER AND ENGAGEABLE BY SAIDDEAD LEVER BRAKE BEAM, AND A LEVER MEANS ENGAGEABLE WITH SAID PISTONMEANS TO OPERATE SAID BRAKE BEAMS, SAID LEVER MEANS BEING DISPOSED ONTHE OTHER SIDE OF THE BOLSTER OPPOSITE SAID CYLINDER MEANS AND SAIDSLACK ADJUSTER.